Study finds toxic metals from 2023 Maui wildfires harmed residents' lung health months after fires

A University of Hawaiʻi study of 1,400 adults reveals that Maui residents had highly elevated levels of toxic metals, including antimony at 40 times national baselines, up to 18 months after the August 2023 wildfires. These elevated metal concentrations, likely sourced from burned buildings and vehicles, are strongly associated with abnormal lung function. The findings suggest that health risks from wildland-urban interface fires persist long after smoke clears, necessitating long-term biomonitoring.

Elevated metal levels in Study participants

• ▪The Maui Wildfire Exposure Study did not establish that tested individuals met the clinical threshold for metal poisoning.
• ▪Maui Wildfire Exposure Study participants had urinary antimony concentrations nearly 40 times, manganese 3.8, barium 2.3, and arsenic 2.2 times higher than United States national reference biomonitoring values.
• ▪A study of 1,400 Maui adults conducted six to 18 months after the August 2023 wildfires found substantially elevated concentrations of several toxic metals in participants' urine.

Impact of metal exposure on lung function

• ▪Wailuku and Kahului residents exhibited some of the highest prevalence of abnormal lung-function measures and the highest median concentrations of copper, iron, and molybdenum.
• ▪Arsenic, cadmium, copper, and antimony were the metals that contributed most strongly to patterns of abnormal lung function in Maui residents.
• ▪Higher combined metal exposure in Maui residents was associated with several measures of abnormal lung function, including reduced breathing capacity.

Maui Wildfire Exposure Study

• ▪The Maui Wildfire Exposure Study measured 24 metals in participants' urine and assessed pulmonary function through standardized breathing tests during the same visit.
• ▪The Maui Wildfire Exposure Study provides participants with access to their individual health results and refers them to care when screening identifies potential health concerns.

Sources of the toxic metal contaminants

• ▪The elevated metal burden in Maui residents likely reflects a complex mixture of wildfire-generated contaminants, geology, and historical agricultural or industrial land use.
• ▪Wildland-urban interface fires burn homes, vehicles, and electronics, generating complex mixtures of metal contaminants that differ from the vegetation smoke typically studied.

Future disaster response recommendations

• ▪Future disaster responses could include targeted assessments of soil, ash, and settled dust, especially in areas with histories of agricultural or industrial contamination.
• ▪Researchers suggest that disaster-response systems must look beyond short-term air monitoring of smoke to include long-term environmental and human biomonitoring.

Impact and cause of the Maui wildfires

• ▪The August 2023 wildfires on Maui destroyed more than 2,200 structures, caused approximately $5.5 billion in damages, and killed more than 100 people in Lahaina.
• ▪The August 2023 Maui wildfires were caused by wind spreading a brushfire that was spurred by downed power lines.

Long-term health impacts of disasters

• ▪Dr. Kekoa Taparra stated that climate-related disasters produce long-lasting health consequences through displacement, healthcare disruption, environmental exposures, and potentially increased mortality.
• ▪Previous studies have found that wildfires and other environmental crises can cause long-term human health impacts, including lung issues and depression.

Debatable claims

• ▪Disaster-response systems should mandate long-term human biomonitoring after major wildfires
• ▪The 2023 wildfires are the primary cause of elevated metal levels in Maui residents
• ▪Elevated metal levels in Maui residents constitute a public health crisis